Process and apparatus for the production of wood pulp



U 1 l 192 March 7 c. J. STERNKOPF PROCESS AND APPARATUS FOR THE PRODUCTION OF WOOD PULP Filed Sept. 28. 1925 l lllullllllllllillll,,..

Patented Mar. 1, 1927.

UNITED STATES PATENT OFFICE.

CHRISTIAN JONATHAN STERNKOPF, OF RITTERSGRUN, GERMANY.

PROCESS AND APPARATUS FOR THE PRODUCTION OF WOOD PULP.

Application filed September 28, 1925, Seria1.No. 59,090, and in Germany May 15, 1924.

It is known to treat wood intended for grinding, before grinding it, in separate open or closed vessels-with cold or hot water, to steam or to boil it, in order to reduce the power required for grinding and to give the wood pulp special qualities.

For that purpose however are required, in addition to the grinding machine, special devices, tanks and the like, and special labour, which renders the working, and the wood pulp produced, more expensive.

On the other hand, it is known to pres the wood in the wood grinding machine against the grindstone with a higher pres sure and less sprinkling water, in order to obtain the so-called wood pulp which is more particularly suitable for conversion to paper.

In order to eliminate special devices and labour, and still to obtain a wood pulp which is better adapted for paper and the like manufacture, according to the present invention the woodis softened, heated, and at the same time constantlysupplied or fed under pressure to the grindstone, in the Wood grinding machine itself, the result being at the same time obtained that the great quantity of heat or quantities of steam generated during the-grinding are utilized for the preliminary preparation of the wood (softening and heating) and therefore for the working process, instead of disappearing as clouds of steam.

The new apparatus for carrying out this new process comprises a wood grinding machine well known in itself, provided with one or more high grinding boxes or magazines, which however is built completely watertight, with stuffing boxes at the spindle passages, etc., and provided with a pulp discharge conduit or channel rising upwards as well as with a new device for the constant supply of wood. The grinding boxes can be surrounded by heating jackets and are provided each with a pipe for the supply of cold or hot water. To prevent the wood from settling down in the grinding machines, are provided stirring devices and water rinsing pipes, and the grindstone is fitted with stirring blades.

A construction of the new wood grinding machine for carrying out the new wood grinding process, is illustrated by way of example in the accompanying drawing in which Figure 1 shows the wood rinding machine in cross section; Figure 2 1n longitudinal section; Figure 3 shows a modified construction in cross section; and Figure 4: shows the machine with two grinding boxes.

Vertically above the grindstone a is arranged a downwardly widening PL'C'IS box or magazine Z), The magazine I) is mounted in a guide 0 of the grinder casing cl, rests on bolts 6 andcan be adjusted when it is Worn at the bottom. The casing d is completely closed and provided with stufiing boxes 9 at the points where the spindle f of the grindstone a passes through the casing. Initead of having the discharge or outlet for the pulp at the bottom, as usual, it is provided with a rising pipe It, so that the pulp comes out here at a levelwhich corresponds to the water level 2' in the magazine b. The grindstone a is therefore completely submerged; in the same way, the wood in the magazine Z) is in water, and the wood passes through water in advancing towards the grindstone a. According to the height of the column of wood in the magazine 6, to the height of the water level-i and to the size of the wood feed, the wood may remain in water for two hours or longer, and in that way is softened and heated before it comes up for grinding. Either hot water is supplied through the pipe ic, or the magazine I) is surrounded by heating jackets Z (Figure 2) into which steam is admitted, or both arrangements are used at the same time in order to heat the water in the magazines and therefore also the wood.

The feed of the wood is produced by spiders or arms m which are Secured to spindles a mounted in the magazine 6, the said spiders or arms projecting, when the spindles are rotated, through slots 0 into the magazine 6 and forcing the wood downwards. The arms on are so shaped that at the top, on entering the magazine b, they force the wood upwards, whilst at the bottom they come out from the box without any jamming. The driving of the spiders m and spindles n is effected by means of spur wheels, worm gears and, belts, from a motor or from a line shaft.

At the point of discharge or outlet of the finished wood pulp from the magazine 1;, are provided pipes 12 adapted to discharge powerful water jets in order to prevent the wood pulp and wood' particles from adhering at these points. The stone sharpener g is arranged in the pulp horizontally, its spindle 1- for the transverse movement, and

. which the sand can settle, and in front a cleaning opening '0. In front of the opening 2), in the interior of the casing is arranged to rotate a stirring device w, and at the end faces of the grindstone a are provided bent scrapers m for the purpose of avoiding accumulation of pulp and of keeping the pulp flowing.

The channel it for the rising pulp has its outlet branch or nozzleg so high that the otherwise necessary pulp pump becomes unnecessary. The pulp flows from the branch :1] out-wards to the shavings collector, from the latter to the strainer and finally to the draining machine, which machines are omit-- ted in the drawing.

According to the construction in Figure 3, the press box or magazine I) is rigidly se cured to the grinder casing 01 but in the interior of the magazine I) are provided adjustable metal lates 2. grinding or reduction of the shavings and fibre there is further provided close to the grindstone a an adjustable stone 1. Above this fine'grinding device, in the casing (Z is mounted the sharpening roller 2. The grindstone a is enclosed by a sieve or strainer P 3 wh ich can be adjusted by means of screws 4 relatively to the stone. To prevent the pul produced from settling in the casing d, t ere is rovided a stirring band 5 going right roun the whole grinder casing d and the pulp pipe h, and guided by means of rollers 6. At places where adjustment is re quired, or where it is necessary to watch from time to time, are provided observation windows.

In place of a single press box or magazine 1), two such boxes or magazines 79 b can be arranged above the grindstone a, as shown in Figure 4.

What I claim and desire to secure by Letters Patent of the United States is:--

1. A process for the production of wood pulp comprising continuously advancing the wood downwardly through a body of water into a grinding zone submerged in the water For the still finer and simultaneously applying artificial heat to subject the wood to gradually increasing pressure and to heat treatment during this advance to the grinding zone.

2. An apparatus for the production of wood pulp comprising a water-tight grinder casing, a grindstone in said casing, a watertight magazine located entirely above the grindstone, a conduit extending from said casing for the discharge of wood pulp, and

means for applying artificial heat to a point above the grindstone to heat the wood during its advance downwardly towards the grindstone and while being exposed to gradually increasing water pressure in said magazine.

3. An apparatus for the production of wood pulp, comprising a water-tight grinder casing, a. grindstone in said casing, a watertight magazine located entirely above said grindstone, atleast one heating jacket surrounding said magazine to heat the wood advancing downwardly to the grindstone and while subjected to gradually increasing water pressure, a conduit extending from said casing for the discharge of wood pulp.

4. An apparatus for the production of wood pulp, comprising a water-tight grinder casing, a grindstone in said casing, a magazine located entirely above said grindstone, a

conduit extending from said casing for the discharge of wood pulp, stirring means ad jacent to the grindstone, agitators for the pulp in the casing, and means for subjecting the wood to gradually increasing water pressure and to heat while advancing downwardly to the grindstone through the magazine.

5. An apparatus for the production of wood pulp comprising a grinder casing, a grindstone mounted in the casing, a magazine located entirely above said grindstone and havingslots therein, rotating arms extending through said slots from both sides of the magazine to engage the wood in the magazine, a conduit extending upwardly from said casing for the discharge of wood pulp, and means for simultaneously subjecting the wood in the magazine to gradually increasing water pressure and to heat during its downward advance to the grindstone.

CHR. JONATHAN STERNKOPF. 

